An exotic use of MPGD muography of Egyptian

An exotic use of MPGD: muography of Egyptian pyramids IRFU/SPh. N: S. Procureur, S. Bouteille (Ph. D) IRFU/Sédi: D. Attié, D. Calvet, P. Magnier, I. Mandjavidze, M. Riallot MPGD workshop, 15/09/2016

BACKGROUND (1/2) → development of 50 x 50 cm² Micromegas with genetic multiplexing 1037 strips, 61 channels • Reduction of electronics (price, consumption) by factor of ~15 • Use of resistive strips to increase S/N and efficiency • 2 D strip readout • CLAS 12/DREAM electronics → first final prototypes available in 2015 (made @ CERN) → CERN ELVIA CERN know how transfer with ELVIA PCB company S. Bouteille et al. , NIM A 834 (2016), 187 (1 st 2 D version) MPGD workshop, 15/09/2016| 2

BACKGROUND (2/2) → building & validation of the first MM-based muon telescope • Temperature fluctuations from 11 to 43°C • Online feedback on T (P) Trigger rate and temperature • Self-triggering mode • Miniaturized electronics box • 30 W of total consumption (bulb) • Operated during 3. 5 months… • … including 1. 5 on solar boards + battery static MPGD workshop, 15/09/2016| 3 S. Bouteille et al. , NIM A 834 (2016), 223 w/o T feedback dynamic w T feedback

THE SCANPYRAMIDS MISSION → Coordinated by Engineering faculty of Cairo & HIP Institute, under authority of antiquity ministry → Imaging of 4 Egyptian pyramids with muons, thermal studies and drones → Mission started in Oct. 2015 with 2 Japanese teams on muon program → Proposition to install MM telescopes outside → Construction of 3 new telescopes of new generation • • • Emulsions & scintillators • Only inside pyramids • CEA joined the mission on April 4 detectors / telescope for redundancy 1 FEU with DREAM asics (512 channels) Thermal protection Improved components => less noise for self-trig. Powered by 220 V AC or solar boards (35 W) 150 Ah battery with regulator 3 G connexion Online data analysis (nano-PC) 2 TB hard disk for each telescope to store raw data 2 B 5 bottles for each telescope (T 2 K gas) • Simulation to optimize the sensitivity Quite challenging schedule! MPGD workshop, 15/09/2016| 4

GOAL OF 1 ST CAMPAIGN → → Observe a known cavity on N-E edge to validate the performance Simulation were performed to optimize the sensitivity for this room • Distance between room and telescopes (solid angle) (the closer the better) • Viewing angle (the higher the better) • Ratio of stone and cavity lengths (the further the better) Already an enormous challenge: detection of a 3 m cavity in 20 m depth rocks, at 150 m distance!!! MPGD workshop, 15/09/2016| 5

PREPARATION OF TELESCOPES (1/2) • Efficiency • Spatial resolution • Gas tightness → Each detector was tested at Saclay before assembly → Outstanding commitment of ELVIA who built 2/3 of the detectors (8) in tight schedule → All 12 showed good performance, with local defects on some (strip cuts) MIP amplitude distribution @ nominal HV MPGD workshop, 15/09/2016| 6

PREPARATION OF TELESCOPES (2/2) → Assembly at Saclay in fly-cases used for the transport & the acquisition Snow! Alhazen (n° 1) MPGD workshop, 15/09/2016| 7 Alvarez (n° 2) 47. 1°C (whole setup tested up to 55°C) Brahic (n° 3)

CAIRO PREPARATIONS → Check tests after transportation, doublet assembly, final plugs → Transportation from University to Giza MPGD workshop, 15/09/2016| 8

GIZA INSTALLATION → Telescopes under tents for safety: 2 on the East face, 1 on North MPGD workshop, 15/09/2016| 9

DATA TAKING → Each detector was operated during 2 to 3 months (gas autonomy) • Number of reconstructed muons with time • Temperature evolution Tmin ~ 23°C; Tmax ~ 40°C Change of gas bottles days → days self triggering: at least 5 planes out of 8 • Ensures at least 3 detectors, means signal from both doublets (lever arm) → Relatively stable acquisition (thanks to T, P feedback) alignment performed early June • Resolution around 300 microns for perpendicular tracks, less than 3 mm from -40 to +40° • 3 mm resolution <=> 1 m uncertainty at 150 m • Contribution of MS in telescope, fly-case and air yield a few tens of centimeters at 150 m → overall statistics: • Alhazen (North): 30. 8 million triggers (4. 5 Hz) • Brahic (East): 24. 6 million triggers (4. 2 Hz) • Alvarez (East): 18. 7 millions (3. 3 Hz) MPGD workshop, 15/09/2016| 10 ~70% are good muon tracks

DATA ANALYSIS (IN PROGRESS) → Some dead channels • Brahic: 5 on a single detector • Alvarez: 4 on a single detector, 1 on a second one → Reprocessing of raw data with new algorithm (old: biggest cluster search) • Convolute the strip amplitude pattern with Gaussian of sigma ~ Nchan/3 • Consider the highest values as cluster seeds • Grow the cluster seed allowing gaps with some criteria (based on number of new, unused channels in the cluster) • Jump dead channels Muon position distribution in problematic Brahic plane Old algo MPGD workshop, 15/09/2016| 11 New algo

DATA ANALYSIS (IN PROGRESS) → Some artefacts in the image are observed (in particular at its center) • Largely due to small bursts of noise during some runs « Bad » run Good run • Also visible in Nchan vs TOT plots MPGD workshop, 15/09/2016| 12 Good run « Bad » run

ONGOING ACTIVITIES → Misalignments appear with time, particularly on Alvarez • Not a day/night effect due to dilatation, but sudden misalignement followed by slow drift in time • Need to understand the origin and re-align without changing direction → Image treatment to find potential anomalies • Edge detection algorithm to check stability of telescopes in time • Slices below the edge at different depths to localize muon excess (or deficit) → Compare East and North projections to look for potential similarities (Geant 4 simulation of a perfectly homogeneous pyramid) MPGD workshop, 15/09/2016| 13

CONCLUSION → Fascinating experiment adventure • Btw, probably the first use of MPGD tracker in Africa (? ) • Proves that MPGD can have applications really far from our daily work → Analysis is still ongoing, results should be soon available → Enormous thank to HIP institute, Cairo University… • Mehdi Tayoubi • Hany Helal, Yasser Elshayeb → … and fantastic local team! • Vincent Steiger, Eric Van Laere, Philippe Bourseiller • Hamada Anwar, Mostaffa Ezzy, Issam, Turbo, etc. , MPGD workshop, 15/09/2016| 14